Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519973
T. Souma, M. Ohtaki
A comparison of detailed structural parameters between the 3IS and Mayer models for the Zn/sub 4-x/Cd/sub x/Sb/sub 3/ system in the Zn-rich region has been successfully performed by the powder XRD study with the Rietveld method using 9 bulk crystals synthesized by vacuum casting method without annealing. The 3IS model gives a better fitting on the Rietveld analysis not only for the undoped Zn/sub 4/Sb/sub 3/ but also for the whole compositional range of the Zn-rich region of the Zn/sub 4-x/Cd/sub x/Sb/sub 3/ compounds. The purities and densities of the bulk crystals exceeded approximately 96 mass% and 95% of XRD density, respectively.
{"title":"Comparison of structural parameters for Zn/sub 4-x/Cd/sub x/Sb/sub 3/ compounds analyzed by the Rietveld method using two crystallographic models","authors":"T. Souma, M. Ohtaki","doi":"10.1109/ICT.2005.1519973","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519973","url":null,"abstract":"A comparison of detailed structural parameters between the 3IS and Mayer models for the Zn/sub 4-x/Cd/sub x/Sb/sub 3/ system in the Zn-rich region has been successfully performed by the powder XRD study with the Rietveld method using 9 bulk crystals synthesized by vacuum casting method without annealing. The 3IS model gives a better fitting on the Rietveld analysis not only for the undoped Zn/sub 4/Sb/sub 3/ but also for the whole compositional range of the Zn-rich region of the Zn/sub 4-x/Cd/sub x/Sb/sub 3/ compounds. The purities and densities of the bulk crystals exceeded approximately 96 mass% and 95% of XRD density, respectively.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114275920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519970
J.E. Rodriguez, D. Cadavid
We report Seebeck coefficient, S(T) and electrical resistivity, /spl rho/(T) measurements of Bi/sub 0.88/Sb/sub 0.12/ compounds prepared by mechanical alloying (MA). The behavior of the Seebeck coefficient and electrical resistivity were studied as a function of temperature and the milling time (MT). The milling process was carried out at room temperature and took different values from 0 hours to 45 hours. The Seebeck coefficient was measured by using the differential method in the temperature range between 77 K and 300 K. S(T) is negative in whole temperature range measured and it changes from -60 /spl mu/V/K for the samples with low milling time up to reach values close to -160 /spl mu/V/K in the samples processed through 45 hours. The thermoelectric power factor, PF increases with the temperature and the milling time, it reaches values close to 5 /spl mu/W/K/sup 2/cm. This result allows us to consider the use of this simple and inexpensive method to grow this kind of thermoelectric materials.
{"title":"Seebeck coefficient of Bi-Sb samples grown by mechanical alloying","authors":"J.E. Rodriguez, D. Cadavid","doi":"10.1109/ICT.2005.1519970","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519970","url":null,"abstract":"We report Seebeck coefficient, S(T) and electrical resistivity, /spl rho/(T) measurements of Bi/sub 0.88/Sb/sub 0.12/ compounds prepared by mechanical alloying (MA). The behavior of the Seebeck coefficient and electrical resistivity were studied as a function of temperature and the milling time (MT). The milling process was carried out at room temperature and took different values from 0 hours to 45 hours. The Seebeck coefficient was measured by using the differential method in the temperature range between 77 K and 300 K. S(T) is negative in whole temperature range measured and it changes from -60 /spl mu/V/K for the samples with low milling time up to reach values close to -160 /spl mu/V/K in the samples processed through 45 hours. The thermoelectric power factor, PF increases with the temperature and the milling time, it reaches values close to 5 /spl mu/W/K/sup 2/cm. This result allows us to consider the use of this simple and inexpensive method to grow this kind of thermoelectric materials.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124192542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519988
M. Ohtaki, K. Shouji
Influence of gas-solid equilibrium and partial pressures of gaseous species was investigated on solid state reactions of Na/sub 2/CO/sub 3/ and Co/sub 3/O/sub 4/ for synthesis of bulk sintered bodies of layered thermoelectric oxide NaCo/sub 2/O/sub 4/. It was revealed that the presence of CO/sub 2/ in the reaction atmosphere strongly inhibits the formation reaction of NaCo/sub 2/O/sub 4/. However, precise control of the CO/sub 2/ partial pressure in the oxygen atmosphere enabled us to avoid otherwise significant Na loss during sintering at temperature as high as 900/spl deg/C, thereby allowing high reaction temperature required for incorporation of Na into the crystal lattice. Selective quantification of the Na species in order to distinguish those within the crystallites and at the grain boundaries revealed that the samples synthesized in the presence of dilute CO/sub 2/ contain more Na in the crystallites with less Na segregation at the boundaries. Improved interconnection between the grains containing larger amounts of Na was suggested as a reason of higher electrical conductivity and larger Seebeck coefficient of the samples thus obtained, compared to the samples containing the same amount of total Na but synthesized in air.
{"title":"Strong influence of CO/sub 2/ partial pressure on inhomogeneous Na distributions and the thermoelectric performance of polycrystalline NaCo/sub 2/O/sub 4/","authors":"M. Ohtaki, K. Shouji","doi":"10.1109/ICT.2005.1519988","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519988","url":null,"abstract":"Influence of gas-solid equilibrium and partial pressures of gaseous species was investigated on solid state reactions of Na/sub 2/CO/sub 3/ and Co/sub 3/O/sub 4/ for synthesis of bulk sintered bodies of layered thermoelectric oxide NaCo/sub 2/O/sub 4/. It was revealed that the presence of CO/sub 2/ in the reaction atmosphere strongly inhibits the formation reaction of NaCo/sub 2/O/sub 4/. However, precise control of the CO/sub 2/ partial pressure in the oxygen atmosphere enabled us to avoid otherwise significant Na loss during sintering at temperature as high as 900/spl deg/C, thereby allowing high reaction temperature required for incorporation of Na into the crystal lattice. Selective quantification of the Na species in order to distinguish those within the crystallites and at the grain boundaries revealed that the samples synthesized in the presence of dilute CO/sub 2/ contain more Na in the crystallites with less Na segregation at the boundaries. Improved interconnection between the grains containing larger amounts of Na was suggested as a reason of higher electrical conductivity and larger Seebeck coefficient of the samples thus obtained, compared to the samples containing the same amount of total Na but synthesized in air.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115502671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519890
A. Reddy, E. Siivola, P. Thomas, G. Krueger, R. Venkatasubramanian
A method for evaluating the power conversion efficiency, and hence ZT/sub M/, of thin-film superlattice, bulk single-stage, and segmented-bulk thermoelectric devices is discussed. The challenge in measuring performance of small-scale devices is the difficulty of explicitly measuring temperatures at TE material junctions. An indirect method, using limited thermocouple measurements and electrical voltage/current measurements, will be detailed in this presentation. A temperature gradient is established across the device, and the resulting open-circuit voltage produced is recorded. In the case of a segmented device, a system of equations and unknowns is formulated and solved numerically, taking into account the variation of bulk material properties with temperature. The results are the temperature gradients across each material leg, allowing for computation of the heat transferred, and thus conversion efficiency. A summary of exceptional results are outlined for a single stage thin-film device and a three-stage cascaded device.
{"title":"Measurement and analysis of power conversion efficiency in thin-film and segmented thermoelectric devices","authors":"A. Reddy, E. Siivola, P. Thomas, G. Krueger, R. Venkatasubramanian","doi":"10.1109/ICT.2005.1519890","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519890","url":null,"abstract":"A method for evaluating the power conversion efficiency, and hence ZT/sub M/, of thin-film superlattice, bulk single-stage, and segmented-bulk thermoelectric devices is discussed. The challenge in measuring performance of small-scale devices is the difficulty of explicitly measuring temperatures at TE material junctions. An indirect method, using limited thermocouple measurements and electrical voltage/current measurements, will be detailed in this presentation. A temperature gradient is established across the device, and the resulting open-circuit voltage produced is recorded. In the case of a segmented device, a system of equations and unknowns is formulated and solved numerically, taking into account the variation of bulk material properties with temperature. The results are the temperature gradients across each material leg, allowing for computation of the heat transferred, and thus conversion efficiency. A summary of exceptional results are outlined for a single stage thin-film device and a three-stage cascaded device.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115529420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519923
M. A. Soto, R. Venkatasubramanian
Using Finite Element Analysis (FEA) via ANSYS Workbench simulation software, complicated coupled-field analyses of thermoelectric devices can be performed. This is effective in examining the thermo-mechanical stresses introduced in these devices through their operation. Due to the large temperature gradients inherent in their operation, as well as the mismatch in coefficients of thermal expansion, large stresses can be present during power generation. This stress can lead to device failure in several ways; the device may break, bowing of the system may lead to a loss in thermal contact between layers and subsequent reduction in heat transfer. FEA simulations examined the mechanical behavior of the device at operating temperatures, including; determination of the optimum pellet length for shear stress minimization, and modeling the behavior of Niobium compliance pads in the system.
{"title":"ANSYS-based detailed thermo-mechanical modeling of complex thermoelectric power designs","authors":"M. A. Soto, R. Venkatasubramanian","doi":"10.1109/ICT.2005.1519923","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519923","url":null,"abstract":"Using Finite Element Analysis (FEA) via ANSYS Workbench simulation software, complicated coupled-field analyses of thermoelectric devices can be performed. This is effective in examining the thermo-mechanical stresses introduced in these devices through their operation. Due to the large temperature gradients inherent in their operation, as well as the mismatch in coefficients of thermal expansion, large stresses can be present during power generation. This stress can lead to device failure in several ways; the device may break, bowing of the system may lead to a loss in thermal contact between layers and subsequent reduction in heat transfer. FEA simulations examined the mechanical behavior of the device at operating temperatures, including; determination of the optimum pellet length for shear stress minimization, and modeling the behavior of Niobium compliance pads in the system.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115713955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519991
Xiaofeng Tang, E. Abbott, J. Kolis, K. Aaron, T. Tritt
The thermopower, resistivity and thermal conductivity of NaCo/sub 2/O/sub 4/ single crystals which were grown by typical NaCl flux method were measured by our custom designed systems. A novel low temperature flux method where NaCl/NaOH was used as flux and metallic Co powders as Co source was developed to successfully synthesize Na-deficient Na/sub x/Co/sub 2/O/sub 4/ crystals with size up to 6 mm at low temperature of 550/spl deg/C. The different behavior in resistivity of the crystals grown via low temperature flux method revealed there exist two different types of crystals, one is metallic and another is semiconducting. Measurements on the compact pellet of crystals which were pressed under pressure and temperature revealed the semiconducting resistivity behavior, where energy gap E/sub g/ was found to be 0.09-0.3 eV. The heat capacity and Debye temperature of single crystals are also discussed.
{"title":"Synthesis and physical properties of Na/sub x/Co/sub 2/O/sub 4/ single crystals","authors":"Xiaofeng Tang, E. Abbott, J. Kolis, K. Aaron, T. Tritt","doi":"10.1109/ICT.2005.1519991","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519991","url":null,"abstract":"The thermopower, resistivity and thermal conductivity of NaCo/sub 2/O/sub 4/ single crystals which were grown by typical NaCl flux method were measured by our custom designed systems. A novel low temperature flux method where NaCl/NaOH was used as flux and metallic Co powders as Co source was developed to successfully synthesize Na-deficient Na/sub x/Co/sub 2/O/sub 4/ crystals with size up to 6 mm at low temperature of 550/spl deg/C. The different behavior in resistivity of the crystals grown via low temperature flux method revealed there exist two different types of crystals, one is metallic and another is semiconducting. Measurements on the compact pellet of crystals which were pressed under pressure and temperature revealed the semiconducting resistivity behavior, where energy gap E/sub g/ was found to be 0.09-0.3 eV. The heat capacity and Debye temperature of single crystals are also discussed.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128690895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519995
H. Iwasaki, H. Hori
The Harman method, which is generally utilized in the evaluation of the figure of merit, Z, has been improved to measure several thermoelectric properties. We fabricated equipment for simultaneous measurement of not only the resistivity /spl rho/ and Z but also the Seebeck coefficient /spl alpha/. The thermal conductivity can also be obtained by the calculation of /spl kappa/=/spl alpha//sup 2/ /(/spl rho/ZT). It is pointed out that the evaluation of ZT by the Harman method is equivalent to the determination of the temperature distribution induced in thermoelectric materials when dc current is applied. Furthermore, the equipment is improved to measure thermal heat-flow induced by low frequency ac current. The thermal heat-flow is characterized by the amplitude and the phase delay against the applied current. Fabrication of the equipment is described in detail, where it is emphasized that sufficient thermally isolated conditions are quite important. The experimental results, using the equipment, are shown.
{"title":"Thermoelectric property measurements by the improved Harman method","authors":"H. Iwasaki, H. Hori","doi":"10.1109/ICT.2005.1519995","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519995","url":null,"abstract":"The Harman method, which is generally utilized in the evaluation of the figure of merit, Z, has been improved to measure several thermoelectric properties. We fabricated equipment for simultaneous measurement of not only the resistivity /spl rho/ and Z but also the Seebeck coefficient /spl alpha/. The thermal conductivity can also be obtained by the calculation of /spl kappa/=/spl alpha//sup 2/ /(/spl rho/ZT). It is pointed out that the evaluation of ZT by the Harman method is equivalent to the determination of the temperature distribution induced in thermoelectric materials when dc current is applied. Furthermore, the equipment is improved to measure thermal heat-flow induced by low frequency ac current. The thermal heat-flow is characterized by the amplitude and the phase delay against the applied current. Fabrication of the equipment is described in detail, where it is emphasized that sufficient thermally isolated conditions are quite important. The experimental results, using the equipment, are shown.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128198996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519926
K. Akai, G. Zhao, K. Koga, K. Oshiro, M. Matsuura
Transition element(TM) doping for group IV clathrates is very interesting from the viewpoint of p-type thermoelectric materials. Group IV clathrates are candidates of high performance thermoelectric materials, because they show low thermal conductivity and high carrier mobility. But almost all clathrate semiconductors show n-type conduction due to excess electrons brought by alkali or alkaline-earth metal elements. We have studied the doping effects of noble metal elements on the electronic structure and thermoelectric properties by means of computational approaches. The electronic structure is calculated by the Full-potential Linearized Augmented Plane Wave (FLAPW) method with the Generalized Gradient Approximation (GGA) based on the density functional theory. The calculated electronic structure shows that TM-substituting clathrates Ba/sub 8/M/sub 6/X/sub 40/(M=Cu, Ag, Au; X=Si, Ge) are p-type semiconductors and have large thermoelectric power(/spl alpha/) at room temperature. The calculated energy of the band gap E/sub g/ is 302 meV in Ba/sub 8/Au/sub 6/Ge/sub 40/, which is smaller than that in Ba/sub 8/Ga/sub 16/Ge/sub 30/(E/sub g/=513 meV ). When La atoms are doped at guest sites, the band gap becomes large: E/sub g/=353 meV(La/sub 2/Ba/sub 6/Au/sub 6/Ge/sub 40/). By using a rigid band and a constant relaxation time approximation, we have calculated the thermoelectric properties. For La/sub 2/Ba/sub 6/Au/sub 6/Ge/sub 40/, we obtained /spl alpha/=240 /spl mu/V/K at a hole concentration n/sub h/=10/sup 20//cm/sup 3/ and at 300 K.
{"title":"Electronic structure and thermoelectric properties on transition-element-doped clathrates","authors":"K. Akai, G. Zhao, K. Koga, K. Oshiro, M. Matsuura","doi":"10.1109/ICT.2005.1519926","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519926","url":null,"abstract":"Transition element(TM) doping for group IV clathrates is very interesting from the viewpoint of p-type thermoelectric materials. Group IV clathrates are candidates of high performance thermoelectric materials, because they show low thermal conductivity and high carrier mobility. But almost all clathrate semiconductors show n-type conduction due to excess electrons brought by alkali or alkaline-earth metal elements. We have studied the doping effects of noble metal elements on the electronic structure and thermoelectric properties by means of computational approaches. The electronic structure is calculated by the Full-potential Linearized Augmented Plane Wave (FLAPW) method with the Generalized Gradient Approximation (GGA) based on the density functional theory. The calculated electronic structure shows that TM-substituting clathrates Ba/sub 8/M/sub 6/X/sub 40/(M=Cu, Ag, Au; X=Si, Ge) are p-type semiconductors and have large thermoelectric power(/spl alpha/) at room temperature. The calculated energy of the band gap E/sub g/ is 302 meV in Ba/sub 8/Au/sub 6/Ge/sub 40/, which is smaller than that in Ba/sub 8/Ga/sub 16/Ge/sub 30/(E/sub g/=513 meV ). When La atoms are doped at guest sites, the band gap becomes large: E/sub g/=353 meV(La/sub 2/Ba/sub 6/Au/sub 6/Ge/sub 40/). By using a rigid band and a constant relaxation time approximation, we have calculated the thermoelectric properties. For La/sub 2/Ba/sub 6/Au/sub 6/Ge/sub 40/, we obtained /spl alpha/=240 /spl mu/V/K at a hole concentration n/sub h/=10/sup 20//cm/sup 3/ and at 300 K.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116873067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519996
Zheng Zhang, Xiaopeng Xie, Yutao Luo
The thermoelectric generator used for recovered the waste heat of vehicle engine exhaust-gas, is a conversion device between the waste heat flow field and the change electric field, and the temperature field is the coupling field between them. One of the methods to increase the conversion efficiency of this type generator is to strengthen the conversion intensity among above fields. In this paper, a new internal-axial-netted thermoelectric generator is presented, which uses the 'stereo-electrodes' to touch and convect with the heat gas flow directly; uses the compensating wire to link separated cold source to make a great temperature difference. Though it uses the existing thermoelectric materials, the out-power density can be increased. The hybrid electric vehicle (HEV) equipped with engine and generator is a transitional type from the internal-combustion engine vehicle to electric, but a self-existent one. In this paper, the application scheme and key technologies of above high-intensity thermoelectric generator (HTG) as the main to supply electric power in HEV are also discussed.
{"title":"Research on the novel high-intensity thermoelectric generator and its application on HEV","authors":"Zheng Zhang, Xiaopeng Xie, Yutao Luo","doi":"10.1109/ICT.2005.1519996","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519996","url":null,"abstract":"The thermoelectric generator used for recovered the waste heat of vehicle engine exhaust-gas, is a conversion device between the waste heat flow field and the change electric field, and the temperature field is the coupling field between them. One of the methods to increase the conversion efficiency of this type generator is to strengthen the conversion intensity among above fields. In this paper, a new internal-axial-netted thermoelectric generator is presented, which uses the 'stereo-electrodes' to touch and convect with the heat gas flow directly; uses the compensating wire to link separated cold source to make a great temperature difference. Though it uses the existing thermoelectric materials, the out-power density can be increased. The hybrid electric vehicle (HEV) equipped with engine and generator is a transitional type from the internal-combustion engine vehicle to electric, but a self-existent one. In this paper, the application scheme and key technologies of above high-intensity thermoelectric generator (HTG) as the main to supply electric power in HEV are also discussed.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"2 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114134491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519888
E. Siivola, P. Thomas, K. Coonley, A. Reddy, J. Posthill, B. Cook, R. Venkatasubramanian
Segmented bulk single-couple devices have been fabricated using SiGe, PbTe, and TAGS materials. Initial optimization studies have yielded power generation efficiencies in excess of 12%, with cold-side temperatures of /spl sim/175/spl deg/C and hot-side temperatures of /spl sim/700/spl deg/C. The goal is to cascade these devices with high-performance Bi/sub 2/Te/sub 3/-superlattice cold-stage operating between 25/spl deg/C to 175/spl deg/C. We will be discussing the trade space between segmented and cascaded assemblies as it relates to the thermal and electrical matching between the different layers and device complexity. It will be shown how layer matching affects overall device performance and how this knowledge can be used to determine the optimal design. We will also discuss the methodologies used to meet the various challenges of high temperature materials assembly including ohmic contacts, diffusion barriers, and CTE induced stresses. Measurement results of device performance will be provided to illustrate the consequences of the methodologies used. We will also include results from early integration of these 2-stage segmented devices to thin-film superlattice cold-stage device to yield three stage power devices.
{"title":"High efficiency segmented bulk devices cascaded with high-performance superlattice cold-stage","authors":"E. Siivola, P. Thomas, K. Coonley, A. Reddy, J. Posthill, B. Cook, R. Venkatasubramanian","doi":"10.1109/ICT.2005.1519888","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519888","url":null,"abstract":"Segmented bulk single-couple devices have been fabricated using SiGe, PbTe, and TAGS materials. Initial optimization studies have yielded power generation efficiencies in excess of 12%, with cold-side temperatures of /spl sim/175/spl deg/C and hot-side temperatures of /spl sim/700/spl deg/C. The goal is to cascade these devices with high-performance Bi/sub 2/Te/sub 3/-superlattice cold-stage operating between 25/spl deg/C to 175/spl deg/C. We will be discussing the trade space between segmented and cascaded assemblies as it relates to the thermal and electrical matching between the different layers and device complexity. It will be shown how layer matching affects overall device performance and how this knowledge can be used to determine the optimal design. We will also discuss the methodologies used to meet the various challenges of high temperature materials assembly including ohmic contacts, diffusion barriers, and CTE induced stresses. Measurement results of device performance will be provided to illustrate the consequences of the methodologies used. We will also include results from early integration of these 2-stage segmented devices to thin-film superlattice cold-stage device to yield three stage power devices.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124077455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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